Kevin Mitchell enters the ring at Upton Park tomorrow against the hard-punching Michael Katsidis hoping to crown a lifelong passion for fighting, which he claimed once included taking on "15 or 20 kids" at once when younger, by taking the Australian's interim WBO world lightweight title.

The 25-year-old Mitchell, who is unbeaten in 31 fights, admitted that he was a tearaway when growing up in nearby Dagenham. "When I was younger I was a scrapper and a little shit," he said. "From seven or eight I was out on the street or in school fighting all the time. I was always hitting people. I liked watching Bruce Lee, Jean-Claude Van Damme and Steven Seagal films – I just loved fighting. It was against bigger kids as well – lads who were three or four years older than me.

"I remember the time there were 15 or 20 kids causing trouble outside my mum's house. I went outside and fought them all. I was never scared – it was just the way I was. My dad was a tough guy so it probably came from him. My mum's a lovely lady but she's a no-nonsense sort of person. It was natural. It was just in me. It was lucky I found boxing, otherwise I could have been like some of my friends, in prison."

Katsidis, who is 29, has two defeats from his 28 professional fights, which have featured a finer calibre of opponent than Mitchell. The two reverses came against former world champions, Joel Casamayor and Juan Díaz.

Last December Mitchell offered a surprisingly smart 12-round dismantling of Breidis Prescott, the hard-fisted Colombian who embarrassed Amir Khan in 54 seconds in 2008. Khan, who also fights tonight when he puts his WBA lightweight title on the line against Paulie Malignaggi at Madison Square Garden, is Mitchell's dream opponent.

Regarding the performance against Prescott, Mitchell added: "When Prescott came over he was saying how hard his life had been. Well I was struggling to pay a mortgage on my own at 18 with two kids. I'm not hungry, I'm starving. Winning a world title would mean I could secure my children's future. I don't want them growing up hard like I did."

James DeGale, the Olympic middleweight champion, will face a first 12-round contest when he fights Sam Horton for WBA international super-middleweight title. Danny Williams, in his last professional bout, defends his British heavyweight title against Derek Chisora.